Prem Singh of the Congress, who is also known as the 'Bhisham Pitamah' of Delhi politics, Tuesday lost the election from Ambedkar Nagar constituency.
He got just 5,336 votes in a constituency from where he had won civic body and assembly elections continuously for a period of 50 years.
Ajay Dutt of AAP won the seat with 66,632 votes being polled in his favour.
Singh, who has also been Delhi assembly speaker, had won thrice with record margins from the constituency.
In 2013, Singh lost the constituency to AAP's Ashok Kumar for the first time since 1958.
