user: ### NOW ANSWER:
Question: How often does a train leave Sealdah?
Columns: ['Train No.', 'Train Name', 'Origin', 'Destination', 'Frequency']
Types: ['text', 'text', 'text', 'text', 'text']
Sample row: ['12067/68', 'Guwahati Jorhat Town Jan Shatabdi Express', 'Guwahati', 'Jorhat', 'Except Sunday']
SQL:

assistant: SELECT "Frequency" FROM "Table" WHERE "Origin" = 'Sealdah';