MySQL Forums :: General :: search criteria - int datatype

Query - col1 and col2 are both int
col2 is primary
col1 also has non clustered index
1) update table1 set col1 = 12 where col2 = '13'

2) update table1 set col1 = '12' where col2 = 13

How these queries will behave?
Are there performance issues as numbers are enclosed in quotes.

I know at mysql will do implicit conversion. Will it take benefit of indexes in both the queries.