user: Question: What's the mean week number when attendance was 63263?
Columns: ['Week', 'Date', 'Opponent', 'Result', 'Attendance']
Types: ['real', 'text', 'text', 'text', 'real']
Sample row: [1.0, 'September 4, 1978', 'Baltimore Colts', 'W 38–0', 64224.0]
SQL:

assistant: SELECT AVG("Week") FROM "Table" WHERE "Attendance" = 63263.0;