CREATE TABLE "losers_knockout" (
  "home_1st_leg" text,
  "home_2nd_leg" text,
  "1st_leg" text,
  "2nd_leg" text,
  "aggregate" text
);

Question: What is the 1st leg for Instituto?
SQL: SELECT "1st_leg" FROM "losers_knockout" WHERE "home_2nd_leg"='instituto';

Question: What Aggregate has a 2-1 1st leg, and is from Belgrano?
SQL: SELECT "aggregate" FROM "losers_knockout" WHERE "1st_leg"='2-1' AND "home_1st_leg"='belgrano';

Question: What Aggregate has a 0-0 1st leg, and a 0-1 second leg?
SQL: SELECT "aggregate" FROM "losers_knockout" WHERE "1st_leg"='0-0' AND "2nd_leg"='0-1';

Question: What aggregate has a 0-0 1st leg, and is from Instituto?
SQL: SELECT "aggregate" FROM "losers_knockout" WHERE "1st_leg"='0-0' AND "home_2nd_leg"='instituto';

Question: What is the home of aggregate's 3-4?
SQL: SELECT "home_2nd_leg" FROM "losers_knockout" WHERE "aggregate"='3-4';