CREATE TABLE table_30836 ("By-election" FLOAT, "Electorate" TEXT, "Date" TEXT, "Incumbent" TEXT, "Reason" TEXT, "Winner" TEXT)

When james rutherford is the incumbent how many dates are there?
SELECT COUNT("Date") FROM table_30836 WHERE "Incumbent" = 'James Rutherford'
SELECT COUNT("Date") FROM "table_30836" WHERE "Incumbent" = 'James Rutherford'