CREATE TABLE table_56621 ("Edition" TEXT, "Round" TEXT, "Date" TEXT, "Partner" TEXT, "Surface" TEXT, "Opponents" TEXT, "Result" TEXT)

Who was Manuela Maleeva opponent when she played a match partnered with michelle strebel?
SELECT "Opponents" FROM table_56621 WHERE "Partner" = 'michelle strebel'
SELECT "Opponents" FROM "table_56621" WHERE "Partner" = 'michelle strebel'