user: Question: What was the air date of the episode that has a production code of 5AKY13?
Columns: ['No. in series', 'No. in season', 'Title', 'Directed by', 'Written by', 'Original air date', 'Production code', 'U.S. viewers (millions)']
Types: ['real', 'real', 'text', 'text', 'text', 'text', 'text', 'text']
Sample row: [85.0, 1.0, '"Harbingers in the Fountain"', 'Ian Toynton', 'Hart Hanson', 'September17,2009', '5AKY01', '10.36']
SQL:

assistant: SELECT "Original air date" FROM "Table" WHERE "Production code" = '5AKY13';