Name the social democratic party for labour
CREATE TABLE "summary_of_election_results_1973_2003" (
  "election" real,
  "labour" real,
  "conservative" real,
  "liberal" real,
  "social_democratic_party" real,
  "social_and_liberal_democrats_liberal_democrats" real,
  "independent" real,
  "green" real,
  "other" text,
  "control" text
);
SELECT "social_democratic_party" FROM "summary_of_election_results_1973_2003" WHERE "control"='Labour';