No, there is no such rule that you have to pass in all sections because only the overall score is considered in DU JAT. If you do not have good command in one of the sections and do good in the other sections, then also you have a chance of getting a good college through DU JAT. However, all the sections of DU JAT are comparatively easier than CBSE papers and generally students do not fail in any of the sections. So, it won't be a difficult task to clear all the sections. Best of Luck.