Which Congress has a # of cosponsors of 19?
CREATE TABLE "legislative_activity" (
  "congress" text,
  "bill_number_s" text,
  "date_introduced" text,
  "sponsor_s" text,
  "num_of_cosponsors" real
);
SELECT "congress" FROM "legislative_activity" WHERE "num_of_cosponsors"=19;