Which Opponents have a Team of arsenal, and a Year of 1963–64?
CREATE TABLE "inter_cities_fairs_cup_uefa_cup_uefa_eur" (
  "year" text,
  "team" text,
  "progress" text,
  "score" text,
  "opponents" text
);
SELECT "opponents" FROM "inter_cities_fairs_cup_uefa_cup_uefa_eur" WHERE "team"='arsenal' AND "year"='1963–64';