The Legislative District of Mindoro was the representation of the Province of Mindoro, in the Philippine Assembly from 1907 to 1916, the Philippine House of Representatives from 1916 to 1935, the Philippine National Assembly from 1935 to 1941 and again in the Philippine House of Representatives from 1941 to 1949, when Occidental Mindoro and Oriental Mindoro—the provinces it was divided into on June 13, 1950—were each granted separate representation.
References
Legislative district of Mindoro Wikipedia(Text) CC BY-SA