WHAT SEASON HAD A SEASON FINALE OF MAY 21, 1989 AND WAS VIEWED BY 17.98 MILLION HOUSEHOLDS?
CREATE TABLE "television_ratings" (
  "season" real,
  "episodes" real,
  "season_premiere" text,
  "season_finale" text,
  "tv_season" text,
  "rank" text,
  "households_millions" real
);
SELECT MAX("season") FROM "television_ratings" WHERE "season_finale"='may 21, 1989' AND "households_millions"<17.98;