TableOne
pocOne    pocTwo
2         3
2         4
1         2

TableTwo
TableTwoId   Name
1            Jones
2            Smith
3            Edwards
4            Camden

select * from TableTwo 
Inner Join TableOne 
on TableTwo.TableTwoId = TableOne.pocOne 
where Name = 'Smith' 
UNION ALL
select * from TableTwo 
Inner Join TableOne 
on TableTwo.TableTwoId = TableOne.pocTwo 
where Name = 'Smith'

select * from TableTwo 
Inner Join TableOne 
on TableTwo.TableTwoId in (TableOne.pocOne, TableOne.pocTwo) 
where Name = 'Smith' 

SELECT * FROM TableTwo 
CROSS JOIN TableZero
INNER JOIN TableOne 
  ON CASE WHEN TableZero.Id = 1 THEN TableOne.pocOne
          ELSE TableOne.pocTwo
     END = TableTwo.TableTwoId
WHERE Name = 'Smith';