user: ### NOW ANSWER:
Question: How many Weeks have a Result of W 17–13?
Columns: ['Week', 'Date', 'Opponent', 'Result', 'Attendance']
Types: ['real', 'text', 'text', 'text', 'text']
Sample row: [1.0, 'September 1, 1991', 'Los Angeles Raiders', 'W 47–17', '61,367']
SQL:

assistant: SELECT AVG("Week") FROM "Table" WHERE "Result" = 'W 17–13';