CREATE TABLE table_18491 ("District" CLOB, "Incumbent" CLOB, "Party" CLOB, "First elected" FLOAT, "Result" CLOB, "Candidates" CLOB)

Name the minumim first elected for alvin bush
SELECT MIN("First elected") FROM table_18491 WHERE "Incumbent" = 'Alvin Bush'
SELECT MIN("First elected") FROM "table_18491" WHERE "Incumbent" = 'Alvin Bush'