Where do I put the amount we pay for our building that we lease for our business?

You can deduct your lease expense under Building or Land Rental Expense on your business tax return (Schedule C for sole proprietors).   You can find it under  Less Common Self-Employment Expenses.  

Rented or leased property includes real estate, machinery, and other items that a taxpayer uses in his or her business and does not own. Payments for the use of this property may be deducted as long as they are reasonable.

Sometimes payments are listed as “rent” when in reality they are actually for the purchase of the property. A conditional sales contract generally exists when at least part of the payments are applied toward the purchase or entitle the taxpayer to acquire the property under advantageous terms. Payments made under a conditional sales contract are not deductible as rent expense but qualify for depreciation expense over the useful life of the asset.