what are every one of the rivals in conclusive where title is zürich
CREATE TABLE "wta_tier_i" (
  "outcome" text,
  "year" real,
  "championship" text,
  "surface" text,
  "partner" text,
  "opponents_in_final" text,
  "score_in_final" text
);
SELECT "opponents_in_final" FROM "wta_tier_i" WHERE "championship"='Zürich';