CREATE TABLE table_37918 ("Date" TEXT, "Score" TEXT, "Set 1" TEXT, "Set 2" TEXT, "Set 3" TEXT, "Total" TEXT)

Which Date has a Set 3 of 21 25?
SELECT "Date" FROM table_37918 WHERE "Set 3" = '21–25'
SELECT "Date" FROM "table_37918" WHERE "Set 3" = '21–25'