Question: Which team 1 has VfL Gummersbach as team 2?
SQL: SELECT "Team 1" FROM "2-15757906-11" WHERE "Team 2" = 'VfL Gummersbach';

Question: What is the 2nd leg that has 31-37 as the 1st leg?
SQL: SELECT "2nd leg" FROM "2-15757906-11" WHERE "1st leg" = '31-37';

Question: Which team 1 has CBM Valladolid as team 2?
SQL: SELECT "Team 1" FROM "2-15757906-11" WHERE "Team 2" = 'CBM Valladolid';

Question: What 2nd leg has RK Gold Club Kozina as team 1?
SQL: SELECT "2nd leg" FROM "2-15757906-11" WHERE "Team 1" = 'RK Gold Club Kozina';

Question: What 1st leg has 52-70 as the agg.?
SQL: SELECT "1st leg" FROM "2-15757906-11" WHERE "Agg." = '52-70';