What was the Int'l Debut for a player in the back position, that also had a Cross Code Debut of RU Australia v Wales?
CREATE TABLE "more_than_one_country" (
  "player" text,
  "int_l_debut" text,
  "year" text,
  "cross_code_debut" text,
  "date" text,
  "position" text
);
SELECT "int_l_debut" FROM "more_than_one_country" WHERE "position"='back' AND "cross_code_debut"='ru australia v wales';