Who is the opponent of game 54, which was in Los Angeles and was before day 18?
CREATE TABLE "schedule_and_results" (
  "game" real,
  "date" real,
  "opponent" text,
  "score" text,
  "location_attendance" text,
  "record" text
);
SELECT "opponent" FROM "schedule_and_results" WHERE "location_attendance"='los angeles' AND "date"<18 AND "game"=54;