user: Question: What was the margin of victory for Isao Aoki when he was a runner-up?
Columns: ['Date', 'Tournament', 'Winning score', 'Margin of victory', 'Runner(s)-up']
Types: ['text', 'text', 'text', 'text', 'text']
Sample row: ['Apr 1, 1990', 'The Tradition at Desert Mountain', '–10 (71-67-68=206)', '4 strokes', 'Gary Player']
SQL:

assistant: SELECT "Margin of victory" FROM "Table" WHERE "Runner(s)-up" = 'Isao Aoki';