CREATE TABLE table_40011 ("Date" TEXT, "Score" TEXT, "Set 1" TEXT, "Set 2" TEXT, "Set 3" TEXT, "Set 4" TEXT, "Set 5" TEXT, "Total" TEXT)

What set 2 has a set 4 of 21-25?
SELECT "Set 2" FROM table_40011 WHERE "Set 4" = '21-25'
SELECT "Set 2" FROM "table_40011" WHERE "Set 4" = '21-25'