Is degree of OPEN UNIVERSITIES/DISTANCE EDUCATION MODE valid in SSC exams

Of course it is valid; read this govt order in regard:

Degrees/diplomas/certificates including technical education degrees/diplomas awarded through Open and Distance Learning mode of education by the Universities established by an Act of Parliament or State Legislature, Institutions Deemed to be Universities under Section 3 of the University Grants Commission Act,1956 and Institutions of National Importance declared under an Act of Parliament stand automatically recognized for the purpose of employment to posts and services under the Central Government provided they have been approved by the University Grants Commission.

NOTE: As per UGC (Open and Distance Learning) Regulations, 2017 published in official Gazette on 23.06.2017, under Part-I (2) (P), the programmes in engineering, medicine, dental, nursing, pharmacy, architecture and physiotherapy etc are not permitted to be offered under Open and Distance Learning mode.