Of all the communist dictators in Eastern Europe in the 20th century, who served the longest in office?

Although Joseph Stalin led the Soviet Union from 1924 to 1953, the date that he became absolute dictator is debated to be around the mid to late 1930s.

Generally, Romania's Nicolae Ceausescu is considered the longest 'serving' Eastern Bloc dictator; ruling for 24 years from 1965 until his (and his wife's) ignominious death on Christmas Day 1989.
http://dictatordata.com/10-longest-ruling-dictators-in-history/
https://en.wikipedia.org/wiki/Nicolae_Ceau?escu

Enver Hoxha of Albania - 41 years.

Enver Halil Hoxha ... was an Albanian communist revolutionary and politician who was the leader of Albania from 1944 until his death in 1985. He was the First Secretary of the Party of Labour of Albania from 1941 until his death, a member of its Politburo, chairman of the Democratic Front of Albania, and commander-in-chief of the Albanian People's Army. He was the twenty-second prime minister of Albania from 1944 to 1954 and at various times was both foreign minister and defence minister of the country.

https://en.wikipedia.org/wiki/Enver_Hoxha