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

### Instruction:
how many porphyria have substrate δ-aminolevulinic acid

### Inputs:
table_name: table, columns: ['Enzyme', 'Location', 'Substrate', 'Product', 'Chromosome', 'EC', 'OMIM', 'Porphyria']

### Response:
SELECT COUNT Porphyria FROM table WHERE Substrate = δ-Aminolevulinic acid