Below is an instruction that describes a task. Write a response that appropriately completes the request.

### Instruction:
What are the population densities of all communes with an are of 28.3 sq.km.?

### Inputs:
table_name: table, columns: ['Commune', 'Area (km 2 )', '2002 population', 'Pop. density (km 2 )', 'Municipality website']

### Response:
SELECT Pop. density (km 2 ) FROM table WHERE Area (km 2 ) = 28.3