CREATE TABLE table_19333752_1 (national_cup VARCHAR, championship VARCHAR)

What is the national cup statistics when the Championship is 21 app / 6 goals?
SELECT national_cup FROM table_19333752_1 WHERE championship = "21 app / 6 goals"
SELECT "national_cup" FROM "table_19333752_1" WHERE "21 app / 6 goals" = "championship"