CREATE TABLE "table1_2668336_19" (
  "district" text,
  "incumbent" text,
  "party" text,
  "first_elected" text,
  "result" text,
  "candidates" text
);

Question: Who were the incumbent(s) in the election featuring  john murray (dr) 50.4% george denison (dr) 49.6% with a result of a retired democratic-republican hold?
SQL: SELECT "incumbent" FROM "table1_2668336_19" WHERE "candidates"='John Murray (DR) 50.4% George Denison (DR) 49.6%' AND "result"='Retired Democratic-Republican hold';

Question: Who were the incumbent(s) when the result was a retired democratic-republican hold and the first elected representative was in 1816>
SQL: SELECT "incumbent" FROM "table1_2668336_19" WHERE "result"='Retired Democratic-Republican hold' AND "first_elected"='1816';

Question: Who were the candidates in the election where william wilson was the incumbent?
SQL: SELECT "candidates" FROM "table1_2668336_19" WHERE "incumbent"='William Wilson';