premise: Mamata Banerjee is an Indian politician in West Bengal.
hypothesis: Mamata Banerjee ( [ mɔmɔt̪a bɔnd̪d̪oˈpad̪ʱˈae̯ ] ( Bengali - মমতা বন্দপাধ্যায় ) also known as Didi was born 5 January 1955 ) is an Indian politician who has been Chief Minister of West Bengal since 2011 . In 2011 Banerjee pulled off a landslide victory for the TMC Congress alliance in West Bengal , defeating the 34-year-old Communist Party of India ( Marxist ) - led Left Front government , the world 's longest-serving democratically elected communist government in the process .