CREATE TABLE table_18129 ("District" TEXT, "Incumbent" TEXT, "Party" TEXT, "First elected" FLOAT, "Results" TEXT, "Candidates" TEXT)

Who were the candidates in district Pennsylvania 3?
SELECT "Candidates" FROM table_18129 WHERE "District" = 'Pennsylvania 3'
SELECT "Candidates" FROM "table_18129" WHERE "District" = 'Pennsylvania 3'