user: Question: When did the episode air that had 7.3 viewers?
Columns: ['Episode', 'Air Date', 'Timeslot', '18-49', 'Viewers']
Types: ['text', 'text', 'text', 'text', 'real']
Sample row: ['Pilot', 'September 24, 2008', 'Wednesday 8:30 P.M.', '2.3/6', 6.84]
SQL:

assistant: SELECT "Air Date" FROM "Table" WHERE "Viewers" = 7.3;