CREATE TABLE table_18739 ("District" CLOB, "Incumbent" CLOB, "Party" CLOB, "First elected" FLOAT, "Result" CLOB, "Candidates" CLOB)

Which District was the incumbent Julius Kahn from? Answer: California 4th district
SELECT COUNT("District") FROM table_18739 WHERE "Incumbent" = 'Julius Kahn'
SELECT COUNT("District") FROM "table_18739" WHERE "Incumbent" = 'Julius Kahn'