Question: What is the team 2 with Cobreloa as team 1?
SQL: SELECT "Team 2" FROM "2-17397131-6" WHERE "Team 1" = 'Cobreloa';

Question: What is the team 1 with a 3-0 2nd leg?
SQL: SELECT "Team 1" FROM "2-17397131-6" WHERE "2nd leg" = '3-0';

Question: What is the team 1 with a 2-1 2nd leg?
SQL: SELECT "Team 1" FROM "2-17397131-6" WHERE "2nd leg" = '2-1';