CREATE TABLE table_18130 ("District" TEXT, "Incumbent" TEXT, "Party" TEXT, "First elected" FLOAT, "Results" TEXT, "Candidates" TEXT)

What's the first elected year of the district whose incumbent is Jim Greenwood?
SELECT MAX("First elected") FROM table_18130 WHERE "Incumbent" = 'Jim Greenwood'
SELECT MAX("First elected") FROM "table_18130" WHERE "Incumbent" = 'Jim Greenwood'