Houston is the largest city in Texas with a population of over 2 Million. There is a major commercial port, Business, Finance, Science and technology are important there. Texas is important for developing manned space flight. 
Houston is moderate, but quite liberal for a city in Texas.
Dubya's father apparently has some influence in Houston, as their main international airport is named after him, as well as his Presidential Library being situated around two hours northwest of Houston.
A rather strange thing for a Texan city is that Annise Parker, an openly lesbian woman was the elected mayor until 2016.
The mayor’s tenure includes passage and implementation of Rebuild Houston, a pay-as-you-go comprehensive street and drainage improvement program that will provide jobs for Houstonians for years to come; voter approval of a $410 million public improvement bond program; creation of an independent organization to oversee the City’s crime lab operations; a unique sobering center for public intoxication cases; adoption of a long-term financial plan that ensures the stability of the City’s water department and reorganization of City departments to achieve cost savings and more efficient operations. She created a new City department focused on the needs of neighborhoods and the Office of Business Opportunity to help minority and women-owned small business enterprises compete for City contracts. Additionally, she won City Council approval of a Historic Preservation Ordinance that, for the first time, provides real protection for historic properties in City-designated historic districts and she issued one of the most comprehensive non-discrimination orders in the nation. 
Overall Annise Parker is doing a great deal that voters in Houston like.