What is the highest First Elected, when Results is "Re-elected", and when Incumbent is "Lincoln Davis"?
CREATE TABLE "tennessee" (
  "district" text,
  "incumbent" text,
  "party" text,
  "first_elected" real,
  "results" text
);
SELECT MAX("first_elected") FROM "tennessee" WHERE "results"='re-elected' AND "incumbent"='lincoln davis';