CREATE TABLE table_55921 ("Season" CLOB, "Club" CLOB, "National League" CLOB, "National Cup" CLOB, "European Cup" CLOB)

Which National League is in 1969-70 season?
SELECT "National League" FROM table_55921 WHERE "Season" = '1969-70'
SELECT "National League" FROM "table_55921" WHERE "Season" = '1969-70'