Dear,
Legal aptitude is one of the section in law entrance exam for UG courses.For the best result in this section there are many books which are really beneficial for the aspirants.here I provide the name of some best book(as per my knowledge) :-
*Legal Aptitude for the CLAT and other Law Entrance Examinations : A Workbook (by A.P Bhardwaj)-. It include all the facts and figures from basics level to high level,which will definitely help us.
*All NCERT Books on political science  of classes 11 and 12.
*A Modern Approach to Logical Reasoning(by R .S Agarwal)
*Our parliament,Our constitution,Our judiciary (By National Book trust)-Really these three books are helps students to buildup their concepts.it contains almost all the information about our parliament, constitution ,as well as about judiciary.
I hope these books help you well.
Thanku