CREATE TABLE table_41644 ("Date" TEXT, "Tournament" TEXT, "Winning score" TEXT, "Margin of victory" TEXT, "Runner ( s ) -up" TEXT)

What was the margin of victory when the winning score was 10 (70-72-68-68=278)?
SELECT "Margin of victory" FROM table_41644 WHERE "Winning score" = '–10 (70-72-68-68=278)'
SELECT "Margin of victory" FROM "table_41644" WHERE "Winning score" = '–10 (70-72-68-68=278)'