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_29289372_1 (area__km²_ VARCHAR, income_classification VARCHAR, population__2010_ VARCHAR)

### Question ###
When 318676 is the population of 2010 and 1st class is the income classification what is the area in kilometers squared?

### Accurate SQL ###

SELECT area__km²_ FROM table_29289372_1 WHERE income_classification = "1st Class" AND population__2010_ = 318676