West Bengal chief minister Mamata Banerjee (extreme left), former Puducherry CM V Narayanasamy (middle) and Assam CM Sarbananda Sonowal. NEW DELHI: The chief minister of any poll-bound state holds a crucial place in the elections. He or she plays a key role in the performance of the ruling party. In the ongoing elections, three such leaders are facing unique challenges this time. TMC supremo Mamata Banerjee had contested and won the 2011 and 2016 assembly elections in West Bengal from Bhowanipore. Usually, sitting chief ministers do not change their constituencies. However, she sprung a surprise by shifting from her traditional seat of Bhowanipore to Nandigram in this election after her former confidante-turned-rival Suvendu Adhikari quit the TMC and joined the BJP in December last year.