On what date did congressman joseph tydings enter take his seat?
CREATE TABLE "earliest_serving_senators_currently_livi" (
  "rank" real,
  "senator" text,
  "date_of_birth" text,
  "entered_senate" text,
  "left_senate" text,
  "state_served" text,
  "party" text,
  "time_since_entry" text
);
SELECT "entered_senate" FROM "earliest_serving_senators_currently_livi" WHERE "senator"='Joseph Tydings';