CREATE TABLE table_28934 ("District" CLOB, "Incumbent" CLOB, "Party" CLOB, "First elected" CLOB, "Result" CLOB, "Candidates" CLOB)

When was the incumbent first elected in the district where the result was a democratic-republican gain?
SELECT "First elected" FROM table_28934 WHERE "Result" = 'Democratic-Republican gain'
SELECT "First elected" FROM "table_28934" WHERE "Result" = 'Democratic-Republican gain'