What aggregate has a 0-0 1st leg, and is from Instituto?
CREATE TABLE "losers_knockout" (
  "home_1st_leg" text,
  "home_2nd_leg" text,
  "1st_leg" text,
  "2nd_leg" text,
  "aggregate" text
);
SELECT "aggregate" FROM "losers_knockout" WHERE "1st_leg"='0-0' AND "home_2nd_leg"='instituto';