tickets = Table('tickets', metadata,
    Column('id', Integer, primary_key=True),
    Column('OpeningDate', DateTime),
    Column('info', String)
    )
metadata.create_all(engine)

class Ticket(object):
    def __init__(self, OpeningDate, info):
        self.OpeningDate = OpeningDate
        self.info = info
    def __repr__(self):
        return '<Ticket("%s", "%s", "%s")>' % (self.id, self.OpeningDate, self.info.encode('cp866', 'ignore'))

mapper(Ticket, tickets)

ticket_date = datetime.datetime.today()

tick = Ticket(ticket_date , u'первая запись')

Session = sessionmaker(bind=engine)
session = Session()
session.add(tick)

query = session.query(Ticket).filter_by(OpeningDate = ticket_date).first()