Which series is based in Toronto on may 18?
CREATE TABLE "western_conference_final_vs_3" (
  "date" text,
  "visitor" text,
  "score" text,
  "home" text,
  "decision" text,
  "attendance" real,
  "series" text
);
SELECT "series" FROM "western_conference_final_vs_3" WHERE "home"='toronto' AND "date"='may 18';