CREATE TABLE table_20270 ("No." FLOAT, "Date" CLOB, "Tournament" CLOB, "Winning score" CLOB, "To par" CLOB, "Margin of victory" CLOB, "Runner ( s ) -up" CLOB)

Name the margin of victory when the number is 15
SELECT "Margin of victory" FROM table_20270 WHERE "No." = '15'
SELECT "Margin of victory" FROM "table_20270" WHERE "No." = '15'