What is the Staffel D in the season 1983-84 with a Staffel E of Motor Suhl?
CREATE TABLE "1971_1984" (
  "season" text,
  "staffel_a" text,
  "staffel_b" text,
  "staffel_c" text,
  "staffel_d" text,
  "staffel_e" text
);
SELECT "staffel_d" FROM "1971_1984" WHERE "staffel_e"='motor suhl' AND "season"='1983-84';