Which manager can succeed more, the one who was running after power and has used all means to get the job or one that did not want it, but he was imposed the job because he was the most qualified?

Neither one will be successful at this job. The first one who is only seeking power will abuse the job and will abuse his authority and won't be a good manager, especially if he lacks the needed managerial skills. Also the second one who did not want the job won't be enthusiastic about it and since it was "imposed" on him then he's not motivated to pursue it which means he won't succeed either. 

The one who succeeds in a certain job is the one who is both qualified to do the job and also wants to do it and is intrinsically motivated to pursue success for himself, for others and for the organization through this job.