user: Question: What was the margin of victory in the tournament with a winning score of −3 (74-68-72-71=285)?
Columns: ['Date', 'Tournament', 'Winning score', 'Margin of victory', 'Runner(s)-up']
Types: ['text', 'text', 'text', 'text', 'text']
Sample row: ['9 Jul 1954', 'The Open Championship', '−9 (72-71-69-71=283)', '1 stroke', 'Bobby Locke , Dai Rees , Syd Scott']
SQL:

assistant: SELECT "Margin of victory" FROM "Table" WHERE "Winning score" = '−3 (74-68-72-71=285)';