After a long long time I read The Hindu and found this.
....Curiously, it is Prime Minister Manmohan Singh, who has no known electoral base and holds office by virtue of being a member of the Rajya Sabha, who has been allowed to pull the trigger on the political arrangement ......How many times have Sitaram Yechuri and Prakash Karat been elected to Lok Sabha? I lack general awareness. So, please let me know.