As per Section 151 (a) of the Representation of People Act, 1950, a by-election can be held within a period of six months from the date of occurrence of the vacancy.
"But there is a provision which says that if the remaining term of the member in relation to the vacancy is one year or less, the by-election will not be held," Pyngrope said.
Assembly elections in Meghalaya are due in less than a year.
The Speaker said Sangma's resignation letter has been forwarded to the Election Commission.
The former Lok Sabha Speaker had put down his papers as primary member of the NCP and as an MLA on Wednesday to contest the Presidential election.
The BJP, AIADMK and BJD have expressed their support to Sangma's candidature.