user: Question: What date did the episode with a production code of 447004 originally air?
Columns: ['No. in series', 'Title', 'Directed by', 'Written by', 'Original air date', 'Production code']
Types: ['real', 'text', 'text', 'text', 'text', 'real']
Sample row: [1.0, '"Pilot"', 'Richard Correll', 'William Bickley & Michael Warren', 'September 20, 1991', 475049.0]
SQL:

assistant: SELECT "Original air date" FROM "Table" WHERE "Production code" = 447004.0;