Bundesliga champions Bayer Leverkusen missed several big chances to score and ended up held to a goalless draw at home by last season’s runners-up VfB Stuttgart on Friday. Leverkusen should have broken the deadlock in the first half, after hitting the woodwork and putting goalkeeper Alexander Nübel under pressure a number of times. When they finally found the net, however, Jeremie Frimpong’s goal was ruled out because assist provider Victor Boniface was offside and let the ball go out before crossing into the box. The second half had an intense start, with Leverkusen asking for a penalty in th…