user: Question: What's the code of the district in which 312520 people lived in 2011?
Columns: ['Code', 'District', 'Headquarters', 'Population (2001 Census)', 'Population (2011 Census)', 'Area (km²)', 'Density in 2011 (/km²)']
Types: ['text', 'text', 'text', 'real', 'real', 'real', 'text']
Sample row: ['AN', 'Anugul', 'Anugul', 1140003.0, 1273821.0, 6375.0, '199.8']
SQL:

assistant: SELECT "Code" FROM "Table" WHERE "Population (2011 Census)" = 312520.0;