"Laschet is still a long way from the chancellor's office," the Sueddeutsche Zeitung daily said. But the poll result has brought him "much closer to it".
The CDU under new party chief Armin Laschet won between 35 and 36 percent of the vote, exit polls showed, with the anti-immigration party on between 22.5 and 23.5 percent.
Although support nationally has stagnated at around 10 to 12 percent for the AfD in recent months, in Saxony-Anhalt -- as in other former East German states -- the party has long had a strong base of support.
Olaf Scholz joins a long list of politicians and officials who have denied responsibility for slipshod oversight and what critical lawmakers see as a pro-Wirecard bias that failed to avert Germany's biggest post-war fraud.
The case, on a par with the Enron scandal in the United States, has prompted the resignation of the heads of two German supervisory authorities, an overhaul of regulation, and criminal investigations.
Long-time Merkel ally Laschet took over as CDU leader in January but has since suffered a series of setback including a damaging spat with Merkel over virus containment measures.
Most of the other production units at the refinery remained shut on following a Wednesday afternoon loss of three steam boilers at the refinery, the sources said.
After restarting the 225,000 bpd CDU, Marathon began on Monday a planned overhaul of the 140,000 bpd fluidic catalytic cracker 3 (FCC 3), the sources said.
On Sunday, FCC 3 had a propane leak that idled activity at the refinery for much of the day, the sources said. No injuries were reported because of the leak.
"In order to avert further damage for my party, I withdraw from my Bundestag mandate," said Nikolas Loebel the conservative Christian Democrats (CDU) party in a statement.
His resignation comes one week before regional elections in the western states of Rhineland-Palatinate and Baden-Wuerttemberg, where Loebel's constituency is.
Laschet, premier of Germany's most populous state and the self-styled Merkel continuity candidate, won 83.35% of the valid postal votes cast by 1,001 delegates.
"The CDU remains Germany's Europe party," Laschet told reporters, stressing that he wanted his leadership of the party to be marked by dialogue with its grass roots.