user: Question: When has a Centerfold model of Krista Kelly?
Columns: ['Date', 'Cover model', 'Centerfold model', 'Interview subject', '20 Questions']
Types: ['text', 'text', 'text', 'text', 'text']
Sample row: ['1-04', 'none', 'Colleen Shannon', 'Jack Nicholson', 'Al Franken']
SQL:

assistant: SELECT "Date" FROM "Table" WHERE "Centerfold model" = 'Krista Kelly';