user: Question: how many 20-39% are in Pont-de-Vivaux?
Columns: ['Quartier', '% 0-19 years', '% 20-39 years', '% 40-59 years', '% 60-74 years', '% 75 years and +']
Types: ['text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['La Capelette', '20,32%', '33,86%', '24,64%', '13,62%', '7,56%']
SQL:

assistant: SELECT "% 20-39 years" FROM "Table" WHERE "Quartier" = 'Pont-de-Vivaux';