That would be «Шкіряни́й учи́тель ма́є де́сять студе́нтів».
But overall, this sentence is strange because студе́нт is usually used for higher educations institutions, a student in the school is у́чень. And учи́тель is normally used for schools, a professor in the higher educations institutions is виклада́ч.
Would it be possible to use "U kozhnoho uchytelya desyat' studentiv." in this context? Is there a contextual or semantic difference? My impression has so far been that the praepositional form for possession tends to predominate, so I find it interesting to see the verb "to have" here.