Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE table_name_50 (population INTEGER, area_km_2 VARCHAR, official_name VARCHAR)

### Question ###
What is the population of northfield parish that has an area less than 342.4?

### Accurate SQL ###

SELECT SUM(population) FROM table_name_50 WHERE area_km_2 < 342.4 AND official_name = "northfield"