There are the National level exam NATA, JEE main Paper II & many state level exam also for B.Arch. admission in which you can appear.

NATA Eligibility CriteriaYou must passed/appearing in 10+2 or equivalent exam from a recognised board with Mathematics as one of the subjects (with 50% marks) are eligible to appear in NATA 2017.  

For further you can go through with given below link.

NATA Eligibility

JEE Main PaperII Eligibility:

You should have 5 subjects for B.Arch/ B.Planning are:

1-Language, 2-Physics, 3-Mathematics (compulsory), 4-Any one of (Chemistry, Biology, Biotechnology, Technical Vocational Subject), 5-Any other subject

For further you can go through with given below link.

JEE Main Eligibility

Good Luck!