CREATE TABLE table_70851 ("Date" TEXT, "Tournament" TEXT, "Winning score" TEXT, "Margin of victory" TEXT, "Runner ( s ) -up" TEXT)

What is the Margin of victory on aug 11, 2002?
SELECT "Margin of victory" FROM table_70851 WHERE "Date" = 'aug 11, 2002'
SELECT "Margin of victory" FROM "table_70851" WHERE "Date" = 'aug 11, 2002'