CREATE TABLE table_18661 ("District" TEXT, "Incumbent" TEXT, "Party" TEXT, "First elected" FLOAT, "Result" TEXT, "Candidates" TEXT)

What party is incumbent Oliver H. Cross?
SELECT "Party" FROM table_18661 WHERE "Incumbent" = 'Oliver H. Cross'
SELECT "Party" FROM "table_18661" WHERE "Incumbent" = 'Oliver H. Cross'