YANGON (Reuters) - Myanmar’s main opposition on Wednesday demanded a re-run of a parliamentary election and called for military help to ensure fairness as partial results put Aung San Suu Kyi’s ruling party on course for another commanding victory.The military-backed Union Solidarity and Development Party (USDP) called on authorities to hold another contest as soon as possible “in order to have an election that is free, fair, unbiased and free from unfair campaigning”. The USDP challenge came as the ruling National League for Democracy (NLD) party looked set for its second successive election sweep, with wins in more than 80% of seats so far declared, with about a third of the results announced. The NLD had won 209 of the 249 declared seats in the bicameral legislature compared with 15 for the USDP as of Wednesday night. The NLD needs 322 seats to form the next government and has already claimed victory in Sunday’s contest. The NLD won by a similar margin in the last election in 2015, which was the first vote since the end of nearly 50 years of strict military rule and quasi-military rule. A big win would be a welcome boost for Suu Kyi, a Nobel Peace laureate who has had a turbulent first term and struggled to meet high public expectations. She is tasked with developing a country that suffered decades of decay and required to govern with a military that persecuted her and the NLD for years.