CREATE TABLE table_18148 ("District" TEXT, "Incumbent" TEXT, "Party" TEXT, "First elected" FLOAT, "Results" TEXT, "Candidates" TEXT)

When did the elections take place in district Maryland 2?
SELECT MIN("First elected") FROM table_18148 WHERE "District" = 'Maryland 2'
SELECT MIN("First elected") FROM "table_18148" WHERE "District" = 'Maryland 2'