Failed upgrade with existing Alembic

gistfile1.txt

INFO  [alembic.migration] Context impl PostgresqlImpl.
INFO  [alembic.migration] Will assume transactional DDL.
INFO  [alembic.migration] Running upgrade None -> 1d8e4022d63b
Traceback (most recent call last):
  File "/usr/local/bin/alembic", line 9, in <module>
    load_entry_point('alembic==0.3.7dev', 'console_scripts', 'alembic')()
  File "/usr/local/lib/python2.7/dist-packages/alembic-0.3.7dev-py2.7.egg/alembic/config.py", line 229, in main
    **dict((k, getattr(options, k)) for k in kwarg)
  File "/usr/local/lib/python2.7/dist-packages/alembic-0.3.7dev-py2.7.egg/alembic/command.py", line 121, in upgrade
    script.run_env()
  File "/usr/local/lib/python2.7/dist-packages/alembic-0.3.7dev-py2.7.egg/alembic/script.py", line 192, in run_env
    util.load_python_file(self.dir, 'env.py')
  File "/usr/local/lib/python2.7/dist-packages/alembic-0.3.7dev-py2.7.egg/alembic/util.py", line 185, in load_python_file
    module = imp.load_source(module_id, path, open(path, 'rb'))
  File "alembic/env.py", line 79, in <module>
    run_migrations_online()
  File "alembic/env.py", line 72, in run_migrations_online
    context.run_migrations()
  File "<string>", line 7, in run_migrations
  File "/usr/local/lib/python2.7/dist-packages/alembic-0.3.7dev-py2.7.egg/alembic/environment.py", line 467, in run_migrations
    self.get_context().run_migrations(**kw)
  File "/usr/local/lib/python2.7/dist-packages/alembic-0.3.7dev-py2.7.egg/alembic/migration.py", line 211, in run_migrations
    change(**kw)
  File "alembic/versions/1d8e4022d63b_new_table.py", line 24, in upgrade
    sa.PrimaryKeyConstraint('id')
  File "<string>", line 7, in create_table
  File "/usr/local/lib/python2.7/dist-packages/alembic-0.3.7dev-py2.7.egg/alembic/operations.py", line 534, in create_table
    self._table(name, *columns, **kw)
  File "/usr/local/lib/python2.7/dist-packages/alembic-0.3.7dev-py2.7.egg/alembic/ddl/impl.py", line 148, in create_table
    self._exec(schema.CreateTable(table))
  File "/usr/local/lib/python2.7/dist-packages/alembic-0.3.7dev-py2.7.egg/alembic/ddl/impl.py", line 75, in _exec
    conn.execute(construct, *multiparams, **params)
  File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/engine/base.py", line 727, in execute
    return meth(self, multiparams, params)
  File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/sql/ddl.py", line 67, in _execute_on_connection
    return connection._execute_ddl(self, multiparams, params)
  File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/engine/base.py", line 781, in _execute_ddl
    compiled
  File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/engine/base.py", line 954, in _execute_context
    context)
  File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/engine/base.py", line 1116, in _handle_dbapi_exception
    exc_info
  File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/util/compat.py", line 189, in raise_from_cause
    reraise(type(exception), exception, tb=exc_tb)
  File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/engine/base.py", line 947, in _execute_context
    context)
  File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/engine/default.py", line 435, in do_execute
    cursor.execute(statement, parameters)
sqlalchemy.exc.ProgrammingError: (ProgrammingError) syntax error at or near "utc"
LINE 5: ...AMP WITHOUT TIME ZONE DEFAULT '(now() at time zone 'utc')',
                                                               ^
 "\nCREATE TABLE test (\n\tid BIGSERIAL NOT NULL, \n\tcreated_at TIMESTAMP WITHOUT TIME ZONE DEFAULT 'now()', \n\tcreated_at2 TIMESTAMP WITHOUT TIME ZONE DEFAULT '(now() at time zone 'utc')', \n\tcreated_at3 TIMESTAMP WITHOUT TIME ZONE DEFAULT 'now()', \n\tPRIMARY KEY (id)\n)\n\n" {}