Table schema:
CREATE TABLE table_name_75 (staffel_a VARCHAR, staffel_b VARCHAR, staffel_d VARCHAR, staffel_c VARCHAR)

Question: What is the Staffel A that has a Staffel D of Energie Cottbus and a Staffel C of Chemie Leipzig and a Staffel B of 1. FC Union Berlin?
SQL: SELECT staffel_a FROM table_name_75 WHERE staffel_d = "energie cottbus" AND staffel_c = "chemie leipzig" AND staffel_b = "1. fc union berlin"