CREATE TABLE "round_16_matches" (
  "team_1" text,
  "agg" text,
  "team_2" text,
  "1st_leg" text,
  "2nd_leg" text
);

Question: Which Team 1 has a 2nd leg of 1-3?
SQL: SELECT "team_1" FROM "round_16_matches" WHERE "2nd_leg"='1-3';

Question: What is the Agg for 1st Leg 1-2 and 2nd leg of Withdrew?
SQL: SELECT "agg" FROM "round_16_matches" WHERE "1st_leg"='1-2' AND "2nd_leg"='withdrew';

Question: What is the 2nd leg if the 1st leg is 3-1 and the Team 2 is union sportive de la médina d'alger?
SQL: SELECT "2nd_leg" FROM "round_16_matches" WHERE "1st_leg"='3-1' AND "team_2"='union sportive de la médina d''alger';

Question: What is Team 2 if the 1st Leg is 3-1 and the 2nd Leg is 4-1?
SQL: SELECT "team_2" FROM "round_16_matches" WHERE "1st_leg"='3-1' AND "2nd_leg"='4-1';