Haase got 60.89 percent of votes during the Sunday vote, and her rival, independent candidate Mindaugas Bastys received 35.47 percent of votes.
Voter turnout was 27.08 percent, or 8 413 voters, despite 31 062 people being registered on the local electoral roll.
The by-election in Zanavykai constituency was held after its representative in the parliament, Bastys, renounced his mandate following a failed impeachment and a large protest outside the parliament.
The Constitutional Court earlier ruled that Bastys had breached his oath and committed a gross violation of the Constitution after he hid his ties with a former KGB agent.