High Quality Content by WIKIPEDIA articles! Mario Rafael Diaz-Balart Caballero (born September 25, 1961) is the current U.S. Representative for Florida`s 21st congressional district, serving since 2011. A member of the Republican Party, he was elected in 2010 to succeed his brother, Lincoln Diaz-Balart. The district includes the city of Hialeah, along with several of Miami`s southwestern suburbs. He previously served Florida`s 25th congressional district from 2003 to 2011.