Complex sentence: The oldest regional championship is the one played in La Paz, it started in 1914 and it was considered for many years as the top Bolivian league, even more when it turned into a semi-pro tournament in 1950 and started including teams from Oruro and Cochabamba.
Split into simpler sentences: The oldest regional championship is the one played in La Paz. It started in 1914 and it was considered for many years as the top Bolivian league, especially when it turned into a semi-professional tournament in 1950 and started to include teams from Oruro and Cochabamba.