CREATE TABLE table_24610 ("Season" TEXT, "Timeslot Times listed are Eastern time" TEXT, "Season premiere" TEXT, "Season finale" TEXT, "TV season" TEXT, "Ranking" FLOAT, "Viewers  ( in millions of households ) " TEXT)

When did the season finale ranked at 73 first air?
SELECT "Season finale" FROM table_24610 WHERE "Ranking" = '73'
SELECT "Season finale" FROM "table_24610" WHERE "Ranking" = '73'