CREATE TABLE table_204_996 (id DECIMAL, "no." TEXT, "air date" TEXT, "network" TEXT, "household\ rating" DECIMAL, "viewers\ ( millions ) " TEXT)

which awards ceremony had the same number of viewers as the 18th ?
SELECT "no." FROM table_204_996 WHERE "no." <> 18 AND "viewers\n(millions)" = (SELECT "viewers\n(millions)" FROM table_204_996 WHERE "no." = 18)
SELECT "no." FROM "table_204_996" WHERE "no." <> 18 AND "viewers\n(millions)" = (SELECT "viewers\n(millions)" FROM "table_204_996" WHERE "no." = 18)