user: Question: What was the Margin of victory in the Southwest Golf Classic Tournament?
Columns: ['Date', 'Tournament', 'Winning score', 'Margin of victory', 'Runner(s)-up']
Types: ['text', 'text', 'text', 'text', 'text']
Sample row: ['Sep 28, 1986', 'Southwest Golf Classic', '–13 (68-70-66-71=275)', '3 strokes', 'Tom Byrum']
SQL:

assistant: SELECT "Margin of victory" FROM "Table" WHERE "Tournament" = 'Southwest Golf Classic';