CREATE TABLE table_68972 ("Year" FLOAT, "Opponent" TEXT, "Competition" TEXT, "Score" TEXT, "Venue" TEXT, "Attendance" FLOAT)

When did nswrfl has a score of 8-21?
SELECT "Year" FROM table_68972 WHERE "Competition" = 'nswrfl' AND "Score" = '8-21'
SELECT "Year" FROM "table_68972" WHERE "Competition" = 'nswrfl' AND "Score" = '8-21'