STOCKHOLM—Swedish Prime Minister Stefan Lofven was ousted in a no-confidence vote in parliament on Monday, plunging the country into deep political uncertainty. Lofven, who was defeated after nearly seven years in power over a plan to ease rent controls for new-build apartments, now has a week to resign and hand the speaker the job of finding a new government, or call a snap election. “The government now has a week to decide and we will hold talks with our cooperation parties,” Lovfen told a news conference after the vote. “It is what is best for the country that is important. We will work as fast as we can.” The nationalist Sweden Democrats called the vote after the formerly communist Left Party withdrew support for Lofven’s Social Democrats over the rent control reforms, an important issue for many voters. The no-confidence motion, which required 175 votes in the 349-seat parliament to …