How to get the nth row and nth column of a table in sql server

CREATE TABLE TempTable
      (    
            Sno INT IDENTITY(1,1),
            UserId INT,
            DeptId      INT,
            FirstName varchar(100),
            Lastname varchar(100),
            Email varchar(100),
            IsDeleted bit
      )    
 
INSERT INTO TempTable VALUES(1,2,'John','Smith','jsmith@gamil.com',0)
INSERT INTO TempTable VALUES(1,2,'Tom','Cruse','tcruse@gamil.com',0)
INSERT INTO TempTable VALUES(1,2,'Sunny','Leone','sl@yahoo.com',0)
INSERT INTO TempTable VALUES(1,2,'Kat','Wins','kat@hotmail.com',0)
INSERT INTO TempTable VALUES(1,2,'Amit','Kappa','akappa@gamil.com',0)


 
--SELECT * FROM TempTable

DECLARE @SQLQuery NVARCHAR(2000)
DECLARE @TableName AS NVARCHAR(200)
DECLARE @NthColumn AS INT
DECLARE @NthRow AS NVARCHAR(1000)

DECLARE @ColName AS VARCHAR(100)

SET @TableName ='TempTable'
SET @NthColumn=6
SET @NthRow = '5'

SELECT @ColName = COL_NAME(OBJECT_ID(@TableName),@NthColumn)

SET @SQLQuery = 'SELECT ' + @ColName + ' FROM ' + '(
SELECT *,ROW_NUMBER() OVER (ORDER BY ' + @ColName +' DESC) R FROM  '+@TableName+ ' ) Temp
WHERE R='+ @NthRow

PRINT @SQLQuery
Exec(@SQLQuery)


DROP TABLE TempTable