Who was the opponent of the match on 2006-04-08?
CREATE TABLE "list_of_boxing_quadruple_or_four_divisio" (
  "number" real,
  "name" text,
  "titles" text,
  "date" text,
  "opponent" text,
  "result" text
);
SELECT "opponent" FROM "list_of_boxing_quadruple_or_four_divisio" WHERE "date"='2006-04-08';