CREATE TABLE "second_round_of_16" (
  "team_1" text,
  "agg" text,
  "team_2" text,
  "1st_leg" text,
  "2nd_leg" text
);

Question: What is the 1st leg that has a 2nd leg of 0–0 of olympique khouribga?
SQL: SELECT "1st_leg" FROM "second_round_of_16" WHERE "2nd_leg"='0–0' AND "team_1"='olympique khouribga';

Question: What is the 1st leg of cs sfaxien?
SQL: SELECT "1st_leg" FROM "second_round_of_16" WHERE "team_2"='cs sfaxien';