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

Question: How many 2nd legs had an aggregate of 2-4?
SQL: SELECT COUNT("2nd_leg") FROM "winners_knockout" WHERE "aggregate"='2-4';

Question: How many home (2nd leg) had a 1st leg 1-1?
SQL: SELECT COUNT("home_2nd_leg") FROM "winners_knockout" WHERE "1st_leg"='1-1';

Question: How many 2nd legs are there where home (1st leg) is Independiente?
SQL: SELECT "2nd_leg" FROM "winners_knockout" WHERE "home_1st_leg"='Independiente';

Question: Who was in home (2nd leg) when Talleres was in home  (1st leg)
SQL: SELECT "home_2nd_leg" FROM "winners_knockout" WHERE "home_1st_leg"='Talleres';

Question: Who was in 2nd leg when Boca Juniors was in home (1st leg)?
SQL: SELECT "2nd_leg" FROM "winners_knockout" WHERE "home_1st_leg"='Boca Juniors';