user: Question: WHAT DATE HAD 6 RANK?
Columns: ['Date', 'Opponent#', 'Rank #', 'Site', 'Result', 'Attendance']
Types: ['text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['September 30', 'Texas Christian', '3', 'Ohio Stadium • Columbus, OH', 'T7-7', '82,878']
SQL:

assistant: SELECT "Date" FROM "Table" WHERE "Rank #" = '6';