BERLIN — Germany’s center-left Social Democrats won the biggest share of the vote in a national election Sunday, narrowly beating outgoing Chancellor Angela Merkel ’s center-right Union bloc in a closely fought race that will determine who succeeds the long-time leader at the helm of Europe’s biggest economy. The Social Democrats’ candidate Olaf Scholz, the outgoing vice chancellor and finance minister who pulled his party out of a years-long slump, said the outcome was “a very clear mandate to ensure now that we put together a good, pragmatic government for Germany.” Despite getting its worst-ever result in a federal contest, the Union bloc said it too would reach out to smaller parties to discuss forming a government, while Merkel stays on in a caretaker role until a successor is sworn in. [time-brightcove not-tgx=”true”] Election officials said early Monday that a count of all 299 constituencies showed the Social Democrats received 25.9% of the vote, ahead of 24.1% for the Union bloc.