Bittu had defied the party's boycott decision and is contesting the bypoll as an Independent candidate.
Khadoor Sahib assembly bypolls are scheduled to be held on February 13.
The seat had fallen vacant after Congress' Ramanjit Singh Sikki, the sitting MLA had resigned over incidents of sacrilege in his constituency last year.
The Congress had last week announced that it boycott the Khadoor Sahib by-election, with Amarinder Singh maintaining "since the basic issue of the sacrilege of the holy Guru Granth Sahib, for which Sikki resigned, still remains unresolved, the Congress party decided there was no point in contesting the election".