CREATE TABLE table_61377 ("Round" TEXT, "Opponents" TEXT, "Home" TEXT, "Away" TEXT, "Aggregate" TEXT)

What is the Aggregate of Bayer Leverkusen opponents?
SELECT "Aggregate" FROM table_61377 WHERE "Opponents" = 'bayer leverkusen'
SELECT "Aggregate" FROM "table_61377" WHERE "Opponents" = 'bayer leverkusen'