CREATE TABLE table_204_958 (id NUMBER, "episode" NUMBER, "original broadcast date" CLOB, "average" NUMBER, "rank" NUMBER, "remarks" CLOB)

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))