ROME — Prime Minister Silvio Berlusconi of Italy won a budget vote in Parliament on Tuesday but the tally showed that he no longer has the support of the majority, a huge humiliation that raised the pressure on him to resign in the face of an escalating debt crisis that has hobbled Greece, threatens Italy and could infect the rest of Europe. The budget vote came hours after Umberto Bossi, a key ally in Mr. Berlusconi’s center-right coalition, publicly asked him to step aside for the sake of the country, the euro zone’s third-largest economy and a new epicenter of...