CREATE TABLE table_204_958 (id DECIMAL, "episode" DECIMAL, "original broadcast date" TEXT, "average" DECIMAL, "rank" DECIMAL, "remarks" TEXT)

what is the difference between the average for episode 1 and the average for episode 13 ?
SELECT ABS((SELECT "average" FROM table_204_958 WHERE "episode" = 1) - (SELECT "average" FROM table_204_958 WHERE "episode" = 13))
SELECT ABS((SELECT "average" FROM "table_204_958" WHERE "episode" = 1) - (SELECT "average" FROM "table_204_958" WHERE "episode" = 13))