CREATE TABLE table_61533 ("Official Name" CLOB, "Status" CLOB, "Area km 2" FLOAT, "Population" FLOAT, "Census Ranking" CLOB)

What is the population of northfield parish that has an area less than 342.4?
SELECT SUM("Population") FROM table_61533 WHERE "Area km 2" < '342.4' AND "Official Name" = 'northfield'
SELECT SUM("Population") FROM "table_61533" WHERE "Area km 2" < '342.4' AND "Official Name" = 'northfield'