Question: What is 1st Leg, when Team #2 is "Emelec"?
SQL: SELECT "1st leg" FROM "2-17282875-3" WHERE "Team #2" = 'Emelec';

Question: What is 1st Leg, when Team #1 is "San Lorenzo"?
SQL: SELECT "1st leg" FROM "2-17282875-3" WHERE "Team #1" = 'San Lorenzo';