Hi @Santhosh Kunder ,
Please try the following solution based on tokenization via JSON.
It will work starting from SQL Server 2016 onwards.
We are looking for the 2nd token in the comma separated list of tokens.
JSON array starts from 0 (zero).
SQL
-- DDL and sample data population, start
DECLARE @tbl TABLE (tokens VARCHAR(1000));
INSERT INTO @tbl (tokens) VALUES
('L=CTV,OU=CALUBCO,OU=testext,DC=Test,DC=com');
-- DDL and sample data population, end
SELECT Result = JSON_VALUE(S,'$[1]')
FROM @tbl
CROSS APPLY (VALUES ('["' + REPLACE(STRING_ESCAPE(tokens,'json'),',','","') + '"]')) AS B(S);
Output
+------------+
| Result |
+------------+
| OU=CALUBCO |
+------------+