CREATE TABLE table_22947 ("Season" TEXT, "Club" TEXT, "Country" TEXT, "Championship" TEXT, "National Cup" TEXT, "International Cup" TEXT)

What is the national cup statistics when the Championship is 21 app / 6 goals?
SELECT "National Cup" FROM table_22947 WHERE "Championship" = '21 app / 6 goals'
SELECT "National Cup" FROM "table_22947" WHERE "Championship" = '21 app / 6 goals'