Nitish Kumar, who has served a record 10 terms as Chief Minister of Bihar, surprised political observers on Thursday by filing his nomination papers for the Rajya Sabha elections.

If elected to the Rajya Sabha, Kumar will have to vacate the post of chief minister, which has triggered speculation about a leadership change in the state. Political circles suggest that a leader from the Bharatiya Janata Party could become the next chief minister. If that happens, it would be the first time BJP forms the government with its own chief minister in Bihar.

Reports also indicate that Kumar’s son, Nishant Kumar, could be appointed deputy chief minister in the new government. The move is expected to significantly reshape Bihar’s political landscape.

Kumar, who is also the chief of the Janata Dal (United), filed his nomination in the presence of India’s Home Minister Amit Shah. Earlier in the day, Kumar said he wished to serve in the Rajya Sabha as it is the only house of Parliament he has not yet been a member of.

Kumar has been serving as Bihar’s chief minister since 2005 and said he would continue to support and guide the new government that will be formed in the state.