user: Question: What is the Date of the Tournament with a Winning score of −9 (65-71-68-67=271)?
Columns: ['Date', 'Tournament', 'Winning score', 'Margin of victory', 'Runner(s)-up']
Types: ['text', 'text', 'text', 'text', 'text']
Sample row: ['Sep 11, 1977', 'B.C. Open', '−14 (67-65-69-69=270)', '5 strokes', 'Lee Elder']
SQL:

assistant: SELECT "Date" FROM "Table" WHERE "Winning score" = '−9 (65-71-68-67=271)';