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_204_158 ( id number, "official name" text, "designation" text, "area km2" number, "population" number, "parish" text )

### Question ###
how many municipalities have areas that are below 50 square kilometers ?

### Accurate SQL ###

SELECT COUNT("official name") FROM table_204_158 WHERE "area km2" < 50