Table: female_heads_of_government
Columns: name_a
country
office
mandate_start
mandate_end
term_length

Question: When did Prime Minister Agathe Uwilingiyimana's mandate end?
SQL: SELECT "mandate_end" FROM female_heads_of_government WHERE "office" = 'prime minister' AND "name_a" = 'agathe uwilingiyimana'