user: Question: When did the show directed by Michael DiMartino first air?
Columns: ['No. in series', 'Title', 'Directed by', 'Written by', 'Original air date', 'Production code']
Types: ['real', 'text', 'text', 'text', 'text', 'text']
Sample row: [1.0, '" Death Has a Shadow "', 'Peter Shin', 'Seth MacFarlane', 'January31,1999', '1ACX01']
SQL:

assistant: SELECT "Original air date" FROM "Table" WHERE "Directed by" = 'Michael DiMartino';