Below is an instruction that describes a task. Write a response that appropriately completes the request.

### Instruction:
Name the Nationality / Opponent of the Competition of welsh rugby union challenge trophy and a Result of 38-29?

### Inputs:
table_name: table, columns: ['Date', 'Nationality / Opponent', 'Ground', 'Result', 'Competition']

### Response:
SELECT Nationality / Opponent FROM table WHERE Competition = welsh rugby union challenge trophy AND Result = 38-29