Table schema:
CREATE TABLE table_name_54 (set_3 VARCHAR, set_2 VARCHAR, set_5 VARCHAR, set_1 VARCHAR)

Question: What is set 3 when set 5 is na, set 1 is 21-25, and set 2 is 25-16?
SQL: SELECT set_3 FROM table_name_54 WHERE set_5 = "na" AND set_1 = "21-25" AND set_2 = "25-16"