CREATE TABLE table_18617 ("District" CLOB, "Incumbent" CLOB, "Party" CLOB, "First elected" CLOB, "Result" CLOB, "Candidates" CLOB)

what's the incumbent with result being new seat republican gain
SELECT "Incumbent" FROM table_18617 WHERE "Result" = 'New seat Republican gain'
SELECT "Incumbent" FROM "table_18617" WHERE "Result" = 'New seat Republican gain'