CREATE TABLE table_75829 ("Date" TEXT, "Score" TEXT, "Set 1" TEXT, "Set 2" TEXT, "Set 3" TEXT, "Set 4" TEXT, "Set 5" TEXT, "Total" TEXT)

What is the set 2 the has 1 set of 21-25, and 4 sets of 25-20?
SELECT "Set 2" FROM table_75829 WHERE "Set 1" = '21-25' AND "Set 4" = '25-20'
SELECT "Set 2" FROM "table_75829" WHERE "Set 1" = '21-25' AND "Set 4" = '25-20'