According to the Representation of People Act, 1951
On the question whether a member is subject to disqualification the President's decision is final and the President should obtain the opinion of the election commission and act accordingly
Under 10th schedule (Anti defection law)
The question of disqualification under the 10th schedule is decided by the Chairman in case of the Rajya Sabha and Speaker in case of Lok Sabha, and the decision is subject to judicial review as per Kihoto Hollohan case