CREATE TABLE table_773 ("District" TEXT, "Incumbent" TEXT, "Party" TEXT, "First elected" FLOAT, "Result" TEXT, "Candidates" TEXT)

Who were the candidates when Noble Jones Gregory was incumbent?
SELECT "Candidates" FROM table_773 WHERE "Incumbent" = 'Noble Jones Gregory'
SELECT "Candidates" FROM "table_773" WHERE "Incumbent" = 'Noble Jones Gregory'