CREATE TABLE table_18439 ("District" TEXT, "Incumbent" TEXT, "Party" TEXT, "First elected" FLOAT, "Result" TEXT, "Candidates" TEXT)

When party did the incumbent in the Arkansas 5 district belong to?
SELECT "Party" FROM table_18439 WHERE "District" = 'Arkansas 5'
SELECT "Party" FROM "table_18439" WHERE "District" = 'Arkansas 5'