user: Question: What percentage of the population is below 50% of the median income in the region where 10.4% of the population earns below 40% of the median income?
Columns: ['Region', 'Median income ( Intl.$ )', 'Below 40% of median income', 'Below 50% of median income', 'Below 60% of median income']
Types: ['text', 'real', 'text', 'text', 'text']
Sample row: ['Arica and Parinacota', 7420.0, '9.3%', '17.8%', '24.9%']
SQL:

assistant: SELECT "Below 50% of median income" FROM "Table" WHERE "Below 40% of median income" = '10.4%';