13. (10 points) Fill in the blanks with numbers $1 \sim 3$, so that each row and each column has exactly one number appearing twice. The numbers outside the table indicate the number of numbers visible in that direction, where a number can block any number less than or equal to itself. Therefore, the four-digit number $\overline{\mathrm{ABCD}}$ is . $\qquad$

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【Answer】Solution: According to the problem, we know:
First, analyze the one who can see 1 number, the taller one must be in front, which corresponds to the number 3. Then, based on the number 3 seeing 3 numbers, they can only be arranged in ascending order.

Reasoning leads to:
Therefore, the answer is: 2213.