Table schema:
CREATE TABLE table_30133_1 (gdp_at_constant_prices__thb_trillions_ VARCHAR, current_account_balance__percent_of_gdp_ VARCHAR)

Question: What is the GDP at constant prices for a current account balance of 12.8?
SQL: SELECT gdp_at_constant_prices__thb_trillions_ FROM table_30133_1 WHERE current_account_balance__percent_of_gdp_ = "12.8"