CREATE TABLE "united_states_house_of_representatives_e" (
  "district" text,
  "incumbent" text,
  "party" text,
  "first_elected" real,
  "result" text,
  "candidates" text
);

Question: what year was the first elected incumbant Sidney R. Yates?
SQL: SELECT "first_elected" FROM "united_states_house_of_representatives_e" WHERE "incumbent"='Sidney R. Yates';