Return BLANK is cell value sought is blank
 

I have a INDEX and MATCH formula set to look for certain values in one sheet and return the data from adjacent cells. But, if the cell the formula refers to is blank, it returns a "0" instead of just leaving the cell blank. Does anyone know how I can change my formula:

=INDEX('Sheet1'!D$2:D$192, MATCH(A29,'Sheet1'!C$2:C$178,0))

to return a "BLANK" ??

Any and all assistance will be greatly appreciated.

Thank you